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184

ARMOURED EDENTATES

On the manus, the three inner digits have powerful claws. This
animal, too, was Pleistocene in time. The Megatheriidae had,
however, small as well as <7%antic forms.

The genus Zamierus had a skull no bigger than that of a
Sloth, while Nofkrofherium, was also a comparatively small
creature; the teeth of the latter genus are reduced to |>

The extinct group of the G-Iyptodontidae comprises large
creatures with a dense covering of bony scutes which are arranged
in a tesselated fashion, and thus form an immobile armature of
immense strength. In correspondence with this massive carapace
the dorsal vertebrae have fused together, and the lumbar vertebrae
form a series ankylosed to each other and to the following sacrals.
These creatures are all South American.

Cf-lyptodon, the genus which gives its name to the family, is
known from numerous remains in South America, and also from

FIG. 106.  Glyjotodon clavipes.    x ^.    (After Owen.)

so far north as Texas and Mexico. It grew to be as long as 16
or 17 feet. In the skull there is an exceedingly long
downward process of the zygomatic arch, as in Sloths, the arch
itself being complete. The process extends so far down as to
reach a point about on a level with the middle of the lower jaw.
The nasals are short or rudimentary. As in Myrmecophaga, the
pterygoids enter into the formation of the bony palate. The
lower jaw has a spout-shaped extremity, and, behind, it rises into
an, enormous vertical branch as high as the front part of the jaw
is long. There are eight teeth in each half of each jaw. As in